Injector for refrigerating machines



Patented Nov. 29, 1927.

PATENT OFF-"ICE.

RAOUL BERNAT, O1? BORDEAUX, FRANCE.

INJECTOR FOR REFRIGERATING MACHINES.

Application filed March 20, 1925 Serial No. 17,139, and in France April 18, 1924.

Modern refrigerating machines working with liquefiable gas generally work at superheat, that is to say, only dry gas is admitted I to the compressor. 6 For this purpose a reservoir accumulator is interposed between-the freezing apparatus and the compressor, to collect the liquid par- I ticles which may still be contained in the gas. 10

maximum the transmission of cold, per unit of surface, a powerful circulation is effected in the coils of the freezing apparatus. This result is generally obtained by means of a pump which draws the liquefied gas from the reservoir accumulator and drives it back into the freezing coils.

It is also very important that only the liquefied. gas should pass from the condenser to the freezing apparatus to the exclusion of any still gaseous portion. So the expansion cock needs to be controlled by a skilled operator and requires constant watch- 'The object of the present invention is an automatic device which governs with precision the supply of the liquefied gas to the coils of the freezing apparatus, and also allows the circulation of liquefied gas collected in an auxiliary apparatus such as an accumulator. v

This device comprises in combination an automatic needle valve actuatedby a float and an opposing spring with a second expansion member, an intermediate chamber being" placed between the two members, so that the fall of pressure may take place in two stages and may be automatically Iegu'r lated to a given value.

Solely for the sake of example and to facilitate the understanding of the present description, the accompanying drawing shows one construction of this device in which the injector also effects the forced circulation of liquefied gas arriving throughan adxiliary conduit.

In the construction the device is intended to be interposed between the condenser or liquefier and the freezing apparatus of refrigerating machines. I may further mount upon this device a conduit connecting it with an accumulator ofliquefied gas, so as to again place this gas in the circuit followed by the liquefied gas in the machine.

In these machines, so as to increase to the pressed against its seat 8.by a small spring 9.

In its upper half the float 3 has a perforated division plate which is only provided for the purpose of keeping the'float coaxial with the rod 4. y l

A spring 10 is placed in the casing 11 strong enough to sustain the float 3 and only to allow it to sink when it is filled with the liquefied gas up to about four fifths of its height. I

' A filter 12 prevents access of foreign bodies and impurities to the small channels 13 which lead the liquefied gas to the needle valve.

The passage 14 leads into the chamberl5 which connects with the passage 16 the other end of which contracts into the cone 17 opening into th I cavity 18. provided wiflh a disoharge tube 19. The passage 16 is surrounded by an annular space 20, communicating with the tube 21. A needle valve 22 closes to a greater or less extent the conical end 11 of the passage 16.

The method of operatlon of the above described device is as follows The liquefied gas from the condenser arrives at the opening '2 and falls throu h the orifices 23 into the float 3 which it fll ls. Then the float overflows and the liquefied gas rises in the annular space 24 around the float 3. v

\Vhen this occurs, the spring 10 has only to support the weight of the float 3 less the weight of fluid displaced, because the float is surrounded by liquid. The float 3 is then raised, and the valve 7 is held on its seat by the sprilig 9 until the top 7 of said valve makes contact with a stop 29, and then is drawn forward by the latter. The valve 7 is then raised so that a. certain quantity of liquefied gas riinsout through the passage 14 into the chamber 15.-

After liquefied gas has run out, a gaseous atmosphere surrounds the upper part of the float 3. The relative weight of the float increases in proportion to the fall of level of the liquid in the annular space-24. The float therefore descends again compressing the The cavity 18 is fied gas passes through the passage 16 and flows through the jet 17.

The tube 21 leads liquefied gas from the reservoir accumulator into the annular space 20. The rapid current of liquefied gas in the jet 17 draws a large quantity of liquefied gas from the tube 21 into the nozzle 25 and the Whole of the liquid is ,led by the tube 19 into the coils of the freezing apparatus. These are therefore abundantly bathed with liquid which results in an extremely rapid heat exchange. In practice this forced circulation augments the capacity of heat transference of the coils by 25 to 30%., all other conditions of surface and pressure being equal.

One desirable result of the device described above is that a high pressure is obtained in the chamber 15 owing to the action of the valve 22. The latter by suitably regulating the orifice 17 allows the desired pressure to be maintained in the chamber 15.

To crystallize ideas on the subject-one may take for example a refrigerating machine working with ammonia, with say, a pressure of nine atmospheres in the condenser and of 1 in the freezing apparatus, which are the normal working conditions.

If expansion is effected solely in the device 8, 14, the float has to overcome a pressure of 7 atmospheres. And as it is working with a liquid whose density is only about 0.630 it would have to be made very large.

The above described device, however, allows a pressure of about 7 atmospheres to be maintained in the chamber 15, which gives for the first stage of the expansion :1. diflerence of only 1 atmospheres. This therefore gives a pressure diflerence five times less than that in the case of direct ex pansion and in consequence the volume of the float can be. reduced by four fifths with respect to the volume it must have in the case where the expansion is effected in a single stage. Y

A manometer connected to the chamber 15 allows the pressure in the chamber to be regulated to the most 1 suitable value by means of the valve 22.

and the passage 14, the flow of the liquefied gas is noticeably continuous. The fact has been proved by experience and obviates all shock when the needle descends on to its seating. I

Itmust be observed also that the passage of a considerable quantity of liquid through the nozzle 25 regularizes the flow from the jet 17 and so reacts further to increase the regularity of flow at seating 8 and passage 14. It will be seen that the device according to the present invention enables the two operations, hitherto independent, of regulating the liquefied gas injected and of obtaining a forced circulation to be effected. simulta neously; the operation of a refrigerating machine provided'with this improvement is much more satisfactory.

Having now particularly described and ascertained the 'nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. An automatic regulating injector, comprising, a valve seat, a needle valve for the seat, an open hollow float, a spring tending constantly to raise said float an elastic connection between the valve and the float, an abutment on the float for causing raising of the valve on raising of the float, a casing slightly larger thanthe float and receiving" the same to leave a narrow space between the float and easing, a fluid inlet in the casing for filling the hollow float to overflowing, the weight of the float and its contained liquid forcing the valve to its seat, and overflow from the float, caught in the space between the float and the casing, buoying up the float to raise the valve from its seat.

2. An automatic regulating injector, comprising, a valve seat, a needle valve for the seat, an open hollow float connected to the valve, a spring tending constantly to raise said float acasing slightly larger than the float and receiving the same to leave a small space between the float and casing, a fluid inlet in thecasing for filling the hollow float to overflowing, the weight of the float and its contained liquid forcing the valve to its seat, and overflow from the float, caught in the space between the float and the casing, buoying up the float to raise the valve from its seat.

3. An automatic regulating injector, comprising, a valve seat, a needle valve for the seat, an open hollow float connected to the valve, a spring tending constantly to raise said float, a casing slightly larger than the float and receiving the same to leave a small space between the float and easing, a fluid inlet in the casing for filling the hollow float to overflowing, the weight of the float and its contained liquid forcing the valve to its seat,

and overflow from the float, caught in the space between the float and the casing, buoying up the float to raise the valve from its seat and an elastic connection between the valve and the float.

4. An automatic regulating injector, comprising, two interconnected expansion de' woes, and a chamber positioned intermediate the devices and communicating with'the devices, one of the expansion devices includ+- ing a nozzle, a needle valve adjustably con- RAOUL BERNAT. 

